package com.xiewenyu.dao;

import java.io.IOException;
import java.io.InputStream;
import java.sql.*;
import java.util.Properties;

/**
 * 操作数据库的基础类
 */
public class BaseDao {
    private static String driver;
    private static String url;
    private static String username;
    private static String password;

    static {
        Properties properties=new Properties();
        InputStream in = BaseDao.class.getClassLoader().getResourceAsStream("db.properties");
        try {
            properties.load(in);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        driver=properties.getProperty("driver");
        url=properties.getProperty("url");
        username=properties.getProperty("username");
        password=properties.getProperty("password");

    }

    /**
     * 获取数据库连接
     * @return
     */
    public static Connection getConnection(){

        Connection connection = null;
        try {
            Class.forName(driver);
            connection = DriverManager.getConnection(url);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        return connection;
    }

    //查询公共方法
    public static ResultSet execute(Connection connection, String sql,Object[] params,ResultSet resultSet,PreparedStatement preparedStatement) throws SQLException {
        preparedStatement = connection.prepareStatement(sql);
        for (int i = 0; i < params.length; i++) {
            preparedStatement.setObject(i+1,params[i]);
        }
        resultSet = preparedStatement.executeQuery();
        return resultSet;
    }

    //执行增删改方法
    public static int execute(Connection connection, String sql,Object[] params,PreparedStatement preparedStatement) throws SQLException {
        preparedStatement = connection.prepareStatement(sql);
        for (int i = 0; i < params.length; i++) {
            preparedStatement.setObject(i+1,params[i]);
        }
        int count = preparedStatement.executeUpdate();
        return count;
    }

    //释放连接
    public static boolean closeResource(Connection connection,PreparedStatement preparedStatement,ResultSet resultSet){
        boolean flag=true;
        if(resultSet!=null){
            try {
                resultSet.close();
                //让gc回收
                resultSet=null;
            } catch (SQLException e) {
                e.printStackTrace();
                flag=false;
            }
        }
        if(preparedStatement!=null){
            try {
                preparedStatement.close();
                //让gc回收
                preparedStatement=null;
            } catch (SQLException e) {
                e.printStackTrace();
                flag=false;
            }
        }
        if(connection!=null){
            try {
                connection.close();
                //让gc回收
                connection=null;
            } catch (SQLException e) {
                e.printStackTrace();
                flag=false;
            }
        }
        return flag;
    }
}
